1. Field of the Invention
The present invention relates to an electronic camera applied to a digital camera, for example. More particularly, the present invention relates to an electronic camera, which clamps a raw image signal output from an image sensor.
2. Description of the Prior Art
One example of such a kind of conventional electronic camera is disclosed in Japanese Patent Laying-open No. 2000-278613 laid-open on Oct. 6, 2000. According to this prior art, an optical black level and a preliminary feeding level (a vacant feeding level) are detected from an image signal output from a CCD imager. A clamp timing is switched between an optimal black period and a preliminary feeding period (a vacant feeding period), depending on a difference between the detected levels. However, there exists a level difference between the preliminary feeding level and the optical black level. In the prior art, therefore, a clamp level fluctuates in response to switching of the clamp timing.